The test package contains all regression tests for Python as
well as the modules test.test_support and
test.regrtest. test.test_support is used to enhance
your tests while test.regrtest drives the testing suite.

Each module in the test package whose name starts with
"test_" is a testing suite for a specific module or feature.
All new tests should be written using the unittest module;
using unittest is not required but makes the tests more
flexible and maintenance of the tests easier. Some older tests are
written to use doctest and a ``traditional'' testing
style; these styles of tests will not be covered.